There are three types of insulation used by over 95% of all spa manufacturers
today. They vary in their cost and effectiveness so you should learn about them
before making a spa buying decision.
Basic Insulation
Basic insulation is a single, thin layer of polyurethane applied to the
understructure of a spa shell. It is the least expensive type of insulation and
can dramatically reduce the purchase price of a spa. It is considered a suitable
method of insulation for indoor spas.
However, basic insulation is not adequate for outdoor spas. It’s not capable of
keeping much heat inside the spa so it will be very expensive to heat,
especially in the winter.
Full Foam Insulation
Full foam insulation fills the area between the shell and cabinet sub floor
completely with a thick layer of solid, rigid foam. Over 70% of hot tubs
manufactured today use this method of insulation because it is an excellent way
to insulate and add extra structural support for the hot tub shell. It will
generally keep your heating costs to a minimum whether the spa is located
indoors or out.
There are different types of foam, though, and their insulating qualities vary.
Some spas use low-density, open-cell packaging type foam, which doesn't provide
an adequate amount of insulation, resulting in higher heating costs.
A much better option is multi-layers of high-density, closed-cell polyurethane
foam. This is the same material often used to insulate commercial freezers, and
it will help keep operating costs low. It is generally more efficient at
retaining heat because it does not absorb water.
How do you know if a particular spa has low-density or high-density foam
insulation? Knock on the outside of the spa cabinet and listen to the sound. A
cabinet with low-density foam insulation will sound hollow, while one with
high-density foam insulation will sound solid and sturdy.
Layered Insulation
Sometimes call blanket insulation, layered insulation involves installing layers
of insulating material between the cabinet walls and the spa shell. Look for a
manufacturer who uses multiple layers of materials with insulation values. If
your spa has removable walls, layered insulation is easy to move aside when the
spa needs service. This makes troubleshooting problems quicker and easier,
cutting down on repair costs.
If you want a spa with layered insulation, beware of manufacturers who try to
cut corners. Some will use an inexpensive single layer of insulation with no
insulation along the base, which can result in very expensive heating bills. The
best manufacturers will use multiple layers of a high R-value insulating
material on all four interior cabinet walls, as well as a full layer of
insulation along the base of the cabinet. This gives you the best of both worlds
– easier spa repair and service plus excellent insulation qualities. It will
even provide some level of soundproofing, making your spa quieter to operate.
